Electronic switch



'March 4, 1969 P. BlzET 3,431,435

ELECTRONIC SWITCH Filed Oct. l5, 1965 6? VOLTAGE GENERATOR g I' lofv LI 3 Ibi IC 6i A 5 '1d/1;* 7

AMPLIFIER 9 FLIP.

'l0 FLOPw (25 C) 33 J f- 11- --1 b I :26 29 31E l l '11 'I3 l5 '17 l KEYPER osi` I 'I8 231 B14/23: 4E- i Amai i 3,4 .KEYER [O$;|||19 233g@ i E); 12) 14 1% 20 24E 33 i I 27 s 30 3 )b LS J ss /A/VE/VTO/Z United States Patent O 3,431,435 ELECTRONIC SWITCH Pierre Bizet, Fontenay-auX-Roses, France, assignor to CIT- Compagnie Industrielle des rIelecommunications, Paris, France Filed Oct. 15, 1965, Ser. No. 496,613 Claims priority, application France, ct. 15, 1964,

991,485 U.S. Cl. 307-247 Int. Cl. H0314 17/00, 5/00 13 Claims ABSTRACT 0F THE DISCLOSURE The present invention is directed to an electronic switching device of completely electrical nature having no movable parts and which may `be substituted for known electromechanical relays, particularly for the polarized relays which are currently used in the field of telegraphy.

It is known that such a polarized relay is essentially an electromagnet comprising an inductor coil having several control windings which are insulated with respect to one another, a magnetic circuit including a permanent magnet in one of the branches thereof, a movable armature carrying at least one movable contact, which establishes a circuit with at least one so-called quiescent contact, if the magnetic eld resulting from the currents in the different control windings has a determinate direction, or with a so-called working contact if the magnetic field has an inverse direction; the corresponding switching is generally effected for an excitation of several ampere turns which denes the sensitiveness of the relay. The contacts allow for the circulation of currents in the order of some tens of milli-amperes at the most and having any direction and their resistance is negligible in the circuits being used.

The device according to the present invention reproduces, by means of an electromagnet associated only with passive solid state components and having no mechanical moving parts, the characteristics of such a known polarized relay and particularly the sensitiveness thereof and the isolation of the control windings with respect to one another, to ground, and to the switch contacts; the resistance of the circuits replacing the movable contacts of the prior art is low and allows for a circulation of currents in any direction whatsoever.

Attempts have already been made to utilize solid state circuits to replace the presently used electromechanical telegraphic relays, but none of these devices to date has been capable of providing all of the desired characteristics of such a device, whereas the device according to the present invention makes it possible to obtain these characteristics in a simple and efiicient manner.

It is an object of the present invention to provide an electronic switching device of a completely electrical nature having no mechanical moving parts.

It is another object of the present invention to provide an electronic switching device of the type described having a high sensitivity and electrical isolation between the con` trol windings and the switch contacts.

. ICC

It is a further object of the instant invention to provide an electronic switching device of the type described wherein the impedance characteristics of t-he circuits replacing the movable contacts of known switching arrangements of an electromechanical nature are very favorable and allow for a circulation of currents in either direction.

It is still another object of the instant invention to provide an electronic switching device of the type described which is highly efiicient and compatible with all associated equipment presently in use.

These and other objects, features and advantages of the invention will become more apparent in light of the following specific description taken with the accompanying drawing wherein the sole figure is a schematic diagram of one embodiment of the switching device of the invention.

Looking to the drawing, a magnetic circuit 1 including a core 2 having, for example, four control windings 1a, 1b, 1c, 1d has provided in a gap in the core 2, a rectangular plate 3 cut from a substance having a significant Hall effect, for example, indium arsenide. It is known that such a plate, when subjected to an electric voltage applied between the mid-points of two parallel edges, such as terminals 4 and 5, displays an electromotive force between the mid-points of the other two edges, such as at terminals 7 and 8, if the plate is placed within a magnetic field. For a given direction of the voltage applied at one set of terminals, the electromotive force obtained at the other set of terminals has a certain polarity for a given direction of the magnetic field, and the inverse polarity for the opposite direction of the magnetic field.

In the figure, a generator 6 applies electrical signals, preferably having a given polarity, for example, positive pulses, between the terminals 4 and 5. For a given direction of the magnetic field prevailing in the gap of the core 2 of the magnetic circuit 1, a direction depending upon the current circulation in one of the windings 1a to 1d or of the resultant effect of the currents circulating in the several windings, there will appear between terminal 7, assumed to be connected to ground, and the terminal 8 pulses having a given polarity, for example positive, for the opposite direction of the magnetic field, the pulses appearing between the terminals 7 and 8 will have the inverse polarity, negative for the given example. In the absence of a magnetic field, no output voltage is provided between the terminals 7 and 8.

The pulses appearing at the terminal 8 are amplified in an amplifier 9 and then applied in one or the other of the two possible output conditions thereof to a bistable flipop 10 of conventional configuration. When, for a first polarity of pulses transmitted by the amplifier 9 placing the flip-flop 10 in a first condition, the output of the flipfiop produces energization ofthe primary of a transformer 15 by an oscillator 13 and blocks the energization of a transformer 16 by an oscillator 14. In the second condition of the fiip-flop for the opposite polarity of the pulses transmitted by the amplifier 9, the output of the flip-flop produces energization of the primary of the transformer 15 by the oscillator 13. The means for energizing and de-energizing the oscillators 13 and 14 in response to control from the fiip-fiop 10, which have been identified wit-h reference symbols 11 and 12, and which make use of devices well known per se, Imay either be susceptible of introducing a very Ihigh impedance in series with the oscillator activating the oscillator or by removal thereof they may be susceptible to block the operation of the oscillator.

The output of oscillator 13 transmitted by the secondary of the transformer 15 is applied to a first rectification and filtering arrangement comprising diodes 17 and 18, a resistance 21 and a condenser 38, as well as to a second rectification and filtering arrangement comprising diodes 25 and 26, a resistance 29 and a condenser 40. The diodes 17 and 18 are oriented in one direction and the diodes 25,

26 are oriented in the opposite direction to accommodate both polarities of the transmitted oscillating voltage.

The output of oscillator 14 transmitted by the secondary of the transformer 16 is applied to a` third rectification and filtering arrangement comprising diodes 19 and 20, a resistance 22 and the aforementioned condenser 38, as well as to a fourth rectification and filtering arrangement comprising diodes 27 and 28, oriented in a direction opposite from the diodes 19 and 20, a resistance 30 and the aforementioned condenser 40.

The rectification and filtering arrangements are assumed to be of the type having double alternation but they also be of any other type without departing from the spirit of the present invention.

A common point connected to the resistance 21, the resistance 22 and the condensers 38 is connected to the base B of an NPN transistor 23 and to the base B' of a PNP transistor 24 via a connection 37. A common point connected to the resistance 29, the resistance 30 and the condenser 40 is connected to the base b of a PNP tran sistor 31 and to the base b of an NPN transistor 32 via a connection 39.

The mid-points A and A' of the secondaries of the transformers 15 and 16, respectively, are connected to each other and to a point E common to the emitters of the transistor 23 and 24, by way of connection 36 as well as at a point E common to the emitters of the transistors 31 and 32.

The collectors of the transistors 23 and 31 are connected to a point C, and the collectors of the transistors 24 and 32 are connected to a point C. The point C is, in turn, connected to an output terminal 33; the points E, E' are connected to a neutral output terminal 34; and the point C' is connected to an output terminal 35.

In operation, the polarity of the resultant field generated in the gap of the core 2 due to the control voltages applied to the control windings la--ld determines the polarity of the voltage at terminals '7` and 8, given a Voltage source of given polarity applied to terminals 4 and by generator 6. The voltage at terminals 7 and 8 is amplified by amplifier 9 and applied to the fiip-flop 10, where the polarity thereof determines which output of the ip-fiop will be energized.

It is now assumed that, for a determinate position of the flip-tipp 10, the transformer only is energized with alternating current. The result thereof is that a positive rectified and filtered voltage appears at points B, B' which allows a certain current to pass to the base of transistor 23, the magnitude of current i being determined by the value of the resistance in the base-emitter junction of the transistor 23. In addition, a negative rectified and filtered voltage appears at points b, b', which allows a current of the same order of magnitude to pass to the base of transistor 31, the magnitude being determined by resistance in the 'base-emitter junction of the transistor 31.

If the terminal 33 is brought to a positive potential V of at least several tenths of a volt with respect to terminal 34, the transistor 23 becomes conductive from the collector to the emitter by a current I having a maximum value of i, where 13 is the coefiicient of amplification of the transistor 23 in common emitter connection in the presence of the collector emitter voltage V. If the terminal 33 is brought to a negative potential with respect to the terminal 34, it is the transistor 31 which becomes conductive having a current i. Thus it is evident that in the two cases, if the value of the current I required for operation or control of external circuitry does not exceed the switching arrangement of the invention may be utilized to advantage. The terminal 33 is connected to the terminal 34 during conduction of either transistor 23 or 31 by a low resistance, equal to V/I, whatever may be the polarity of the source connected to the terminal 33. The voltage V'has the value called loss.y

voltage of the transistor 23 or 31.

On the other hand, during the above operation, the

PNP transistor 24 whose base is brought to a positive potential is blocked, as is the NPN transistor 32 whose base is brought to a negative potential. The result thereof is that there is effectively no electrical path between the terminal and the terminal 34.

In a similar manner, it is easily seen that, if for the other position of the flip-op 10 with the transformer 16 being energized to the exclusion of transformer 15, the terminal 35 is connected to the terminal 34 by a low resistance through the transistor 24 or the transistor 32, depending upon the polarity of the source voltage con nected to this terminal, whereas effectively no electrical path is provided between the terminal 33 and the terminal 34 under these circumstances.

It is thus seen that, according to value and polarity of the currents applied to the control windings 1a to 1d, one obtains at will a very low resistance between a first output terminal and a second output terminal and a considerable resistance between said first terminal and a third output terminal and this is achieved with a complete electrical isolation between the input circuits and the output terminals for any desired direction of the current in the output circuit. The sensitiveness of the device to the control currents may be easily adjusted by the regulation of the amplification of the amplifier 9.

The oscillations furnished by the oscillators 13 and 14 having either the same or a different frequency must have a small period with respect to the rates of variation of the control currents. The perfect operation of the device described hereinabove is assured in the best manner under the following conditions, which are easy to observe in actual practice: The positive voltage applied to the base of transistor 23 placing it in the conductive state, taken as an example, is in the order of from 0.2 to 0.3 v. There thus exists at the points B, B a voltage of that order furnished by the diodes 17 and 18 which renders the transistor 23 conductive and blocks the transistor 24. But the reverse or back voltage of the diodes is higher than the forward voltage; it is from 0.5 to 0.7 v., for example. It is thus apparent that the voltage applied to the diodes 19, A2() in their forward direction through resistor 22 does not unblock these diodes. Moreover, even in case where these diodes 19, 20 should be unblocked, the operation would not be seriously jeopardized since the transformer 16 does not receive an alternating voltage under these conditions. There would result merely an unimportant modification of the values of impedance of the circuit.

The scheme presented above may be simplified in the case-being very important in actual practice-where the sources connected to the output terminals 33 and 3S always have the same polarity. This situation is encountered frequently in the field of telegraphy, the terminal 33 being always connected, for example, to a positive voltage source and the terminal 35 to a negative voltage source. Under these circumstances, one may omit the elements included in the outline of the dashed line F, including the transistors 31 and 32 with the rectification and filtering arrangements Which are associated therewith.

If the generator 6 furnishes alternating signals, the plate 3 having the Hall effect furnishes at S currents which are in phase with said signals for a certain polarity of the magnetic field, and inphase opposition for the other polarity. In this case, the amplifier 9 comprises means known per se for furnishing continuous signals whose polarity, being fixed by the polarity of the magnetic field, determines the position of the flip-flop 10.

The single figure presented herein has been given only by way of example for the realization of one embodiment of the present invention and is not intended to limit the scope of the invention thereto, it may have any other designs without departing from the spirit and scope of the present invention.

While I have shown and described several embodiments in accordance with the present invention, it is understood that the same is not limited thereto, but is susceptible of numerous changes and modifications as known to a person skilled in the art and I therefore do not wish to be limited to the details shown and described herein, but intend to cover all such changes and modifications as are encompassed by the scope of the appended claimsA l claim:

1. An electronic switch arrangement for selectively completing a low resistance current path between first and second terminals to the exclusion of a third terminal or between a second and third terminal to the exclusion of a first terminal comprising magnetic circuit means including a magnetic core with a gap and input control windings for generating a magnetic field,

a substantially rectangular lplate made from a material exhibiting Hall effect characteristics positioned within said gap of said magnetic circuit means,

a generator of electrical signals of specific polarity connected at the mid-point of opposite sides of said plate, said plate providing between the mid-points of the remaining sides thereof control signals having a polarity with respect to the signals provided by said generator relating to the direction of said magnetic field,

a bistable flip-flop connected to said plate with said control signals applied to the input thereof for controlling the state thereof in accordance with the polarity of said control signals,

first and second transformer means each including primary and secondary windings,

first and second transformer 4means each including primary and secondary windings,

first and second controlled oscillator means connected respectively to the primary windings of said first and second transformer means, said oscillator means being connected to and controlled by said fiip-flop for complementary operation,

rectifying and filtering means connected to the secondary winding of each of said first and second transfonmer means including a pair of complementary transistors connected in parallel, each pair o-f complementary transistors being connected between a respective transformer means and a respective one of said terminals.

2. An electronic switch arrangement [for selectively completing a low resistance current path between first and second terminals to the exclusion of a third terminal or between a second and third terminal to the exclusion of a first terminal comprising,

magnetic circuit means including a magnetic core with f a gap and input control windings for generating a magnetic field,

a substantially rectangular tplate made from a material exhibiting Hall effect characteristics positioned within said gap of said magnetic circuit means,

a generator of electrical signals of specific polarity connected at the mid-:point of opposite sides of said plate, said plate providing between the mid-points of the remaining sides thereof control signals having a polarity with respect to the signals provided by said -generator relating to the direction of said magnetic field,

a bistable fiipfiop connected to said plate with said control signals applied to the input thereof for controlling the state thereof in accordance with the polarity of said control signals,

first and second transformer means each including primary and secondary windings,

first and second controlled oscillator means connected respectively to the primary windings of said first and second transformer means, said oscillator means Ibeing connected to and controlled by said fiip-fiop for complementary operation,

rectifying and filtering means connected to the secondary winding of each of said first and second transformer means including a pair of complementary transistors connected in parallel, each pair of complementary transistors being connected between a respective transformer means and one of said terminals,

amplifier means connected between said plate and said bistable fiip-op for furnishing a continuous current in response to said control signals and having a polarity corresponding to the direction of said magnetic field.

3. An electronic switch arrangement for selectively completing a low resistance current path between first and second terminals to the exclusion of a third terminal or between a second and third terminal to the exclusion of a first terminal comprising,

magnetic circuit means including a magnetic core with a gap and input control windings for generating a magnetic field,

a substantially rectangular lplate made from a material exhibiting Hall effect characteristics positioned within said gap of said magnetic circuit means,

a generator of electrical signals of specific polarity connected at the mid-:point of opposite sides of said plate, said plate providing between the mid-points of the remaining sides thereof control signals having a polarity with respect to the signals provided by said generator relating to the direction of said magnetic field,

a bistable flip-flop connected to said plate with said control signals applied to the input thereof for controlling the state thereof in accordance with the polarity of said control signals,

first and second transformer means each including primary and secondary windings,

first and second controlled oscillator means connected respectively to the primary windings of said first and second transformer means, said oscillator means being connected to and controlled by said fiip-fiop Ifor complementary operation,

a rectifying and filtering means connected to the secondary winding of each of said first and second transformer means, respectively, each rectifying and filtering means including a pair of complementary transistors connected in parallel, each pair of complementary transistors being connected between a respective transformer means and one of said terminals and each transistor having at least an emitter electrode and a collector electrode,

amplifier means connected between said plate and Said bistable fiip-flop for furnishing a continuous current in response to said control signals and having a polarity corresponding to the direction of said malgnetic field,

said second terminal being connected to the emitter electrodes of the pairs of complementary transistors, said first and third terminals being connected to the collector electrode of a respective pair of complementary transistors.

4. An electronic switch arrangement for selectively completing a low resistance current path between first and second terminals to the exclusion of a third terminal or between a second and third terminal to the exclusion of a first terminal comprising,

magnetic circuit means including a magnetic core with a gap and input control windings for generating a magnetic field,

a substantially rectangular plate made from a material exhibiting Hall effect characteristics positioned within said gap of said magnetic circuit means,

a generator of electrical signals of specific polarity connected at the midpoint of opposite sides of said plate, said plate providing between the mid-points of the remaining sides thereof control signals having a polarity with respect to the signals provided by said generator relating to the direction of said magnetic field,

a bistable flip-fiop connected to said plate with said control signals applied to the input thereof for controlling the state thereof in accordance with the polarity of said control signals,

first and second transformer means each including primary and secondary windings,

first and second -controlled oscillator means connected respectively to the primary windings of said first and second transformer means, said oscillator means being connected to and controlled by said iiip-fiop for complementary operation,

a rectifying and filtering means connected to the secondary winding of each of said first and second transformer means, respectively, each rectifying and filter means including a pair of complementary transistors connected in parallel, each pair of complementary transistors being connected between a respective transformer means and one of said terminals, and each transistor including a base electrode,

the voltage in the secondary winding of said first transformer means being applied to the base electrodes of one pair of complementary transistors and the voltage in the secondary winding of said second transformer means being applied to the base electrodes of the other pair of complementary transistors.

5. An electronic switch arrangement for selectively completing a low resistance current path between first and second terminals to the exclusion of a third terminal or between a second and third terminal to the exclusion of a first terminal comprising,

magnetic circuit means including a magnetic core with a gap and input control windings for generating a magnetic field,

a substantially rectangular plate made from a material exhibiting Hall effect characteristics positioned within said gap of said magnetic circuit means,

a generator of electrical signals of specific polarity connected at the mid-point of opposite sides of said plate, said plate providing between the mid-points of the remaining sides thereof control signals having a polarity with respect to the signals provided by said generator relating to the direction of said magnetic field,

a bistable fiip-fiop connected to said plate with said control signals applied to the input thereof for controlling the state thereof in accordance with the polarity of said control signals,

first and second transformer means each including primary and second windings,

first and second controlled oscillator means connected respectively to the primary windings of said rst and second transformer means, said oscillator means being connected to and controlled by said liip-fiop for complementary operation,

rectifying and filtering means connected to the secondary winding of each of said first and second transformer means including a pair of complementary transistors connected in parallel, each pair of complementary transistors being connected between a respective transformer means and one of said terminals,

said second terminal being connected to the emitter electrodes of both pairs of complementary transistors, said first and third terminals being connected to the collector electrode of a respective pair of complementary transistors,

the voltage in the secondary winding of said first transformer means being applied to the base electrodes of one pair of complementary transistors and the voltage in the secondary winding of said second transformer means being applied to the base electrodes of the other pair of complementary transistors.

6. An electronic switch arrangement of the single-pole double-throw type having no mechanical moving parts comprising,

magnetic circuit means including means for generating a magnetic field of selectively variable direction,

a plate made from a material exhibiting Hall effect characteristics positioned within said magnetic field transversely thereto,

a generator of electrcal signals of specific polarity connected at the mid-point of parallel sides of said plate, said plate providing between the mid-points of other parallel sides control signals having a polarity with respect to the signals provided by said generator relating to the direction of said magnetic field,

bistable means connected to said plate with said control signals applied thereto for generating first and second signals in response to respective polarities of said control signals,

a first controlled voltage source producing a first voltage and a second controlled voltage source producing a second voltage only in response to activation by said first and second signals, respectively,

first, second and neutral output terminals,

first transistor means connected between said first and neutral output terminals and second transistor means connected between said second and neutral output terminals, said first transistor means being biased to conduction by said first voltage and said second transistor means being biased to conduction by said second voltage.

7. An electronic switch arrangement as defined in claim 6 wherein said magnetic circuit means includes a magnetic core with a gap therein and having at least one energizing control winding.

8. An electronic switch arrangement as defined in claim 6 further including amplifier means connected between said plate and said bistable means for amplifying said control signals to produce a continuous control voltage.

9. An electronic switch arrangement as defined in claim 7 wherein said first and second controlled voltage sources each include an output transformer and a rectifying and filtering means for producing a continuous voltage.

10. An electronic switch arrangement as defined in claim 9 further including third transistor means complementary to said frst transistor means and connected in parallel therewith and fourth transistor means complementary to said second transistor means and connected in parallel therewith.

ll. An electronic switch arrangement as defined in claim 9 wherein said bistable means is a flip-flop switchable between binary states in response to the polarity of the applied control signal.

12. An electronic switch arrangement as defined in claim 6 wherein said first and second controlled voltage sources consist of voltage controlled oscillators.

13. An electronic switch arrangement of the single pole double-throw type comprising magnetic circuit means including a magnetic core having a gap therein, at least one energizing control Winding on said core for generating a magnetic field in said gap of selectively variable direction,

a substantially rectangular plate of a material exhibiting Hall effect characteristics positioned in said gap in said core substantially transverse to said magnetic field,

a generator of electrical signals of given polarity connected across the mid-points of a first pair of parallel sides of said plate, said plate providing between the mid-points of the other parallel sides thereof control signals having a polarity with respect to the signals provided by said generator relating to the direction of said magnetic field,

amplifier means connected to the mid-point of one of said other pair of sides of said plate for amplifying said control signals,

a dip-flop with the input thereof connected to said amplifier means and having first and second outputs corresponding to the alternate polarities of Said control signals,

`iirst and second voltage controlled oscillators connected respectively to said rst and second outputs of said ilip-ops, a signal output from said flip-flop serving to activate one or the other of said oscillators,

rst and second transformers-each having a primary winding connected respectively to said irst and second oscillators and a secondary Winding,

a rectifying and ltering arrangement connected to the secondary winding of each of said iirst and second transformers for changing the output of said oscillators to a continuous voltage of given polarity,

first, second and neutral output terminals,

rst and second transistors of complementary type connected parallel with the collectors thereof connected to said first output terminal, the emitters thereof connected to said neutral output terminal and the bases thereof connected to the rectifying and filtering arrangement associated with one of said transformers,

References Cited UNITED STATES PATENTS 3,194,886 7/1965 Mason 178-88 3,221,261 1l/l965 Ertel 330-6 3,230,434 1/ 1966 Bauerlein 307--88-5 XR ARTHUR GAUSS, Primary Examiner.

15 I. ZAZWORSKY, Assistant Examiner.

U.S. C1. X.R. 

